The present invention relates to an apparatus and method for the design and manufacture of foldable integrated stiffeners. These stiffeners may be used in, for example, thin-film arrays of electrochemical devices.
Presently, a need exists for solar arrays that exhibit low weight per unit energy produced, as well as low cost per unit energy produced. Conventional approaches to solar array systems employ complex mechanisms to deploy solar arrays from a folded or collapsed initial state. These mechanisms require the addition of structure to meet the requirements of the array. These structures include, for example, booms. Requirements for these arrays include launch restraint protection, stiffening to meet minimum array natural frequency, deployment mechanisms, and robust structural protection. Conventional technology can only meet these requirements, if at all, through costly and complex mechanisms that require additional structures that add to the cost and weight of the array. Minimum costs using conventional technology are about $1000/Watt. Maximum beginning of life specific power using conventional technology is about 106 Watts/kg.
This invention responds to the problems described above by teaching, for example, novel foldable integrated stiffeners. These stiffeners may be used in, for example, thin-film arrays of electrochemical devices, or in other arrays of devices including foldable arrays of rigid electrochemical devices. In certain embodiments, for example, the cost may be less than $200/Watt and the specific power may be greater than 300 Watt/kg.
An embodiment of the present invention relates to, for example stiffeners, foldable stiffeners, or supporting structures for foldable thin-film arrays of, for example, electrochemical devices. In this embodiment, these structures may include a pair of hingedly attached members that connect to a pair of the electrochemical devices. These members may be collapsible or extensible by folding due to their hinged attachment. Additionally, a third member may supply additional structural support. This member may, for example, be rib-like. It may connect both to one of the electrochemical devices as well as to one of the pair of hinged members connected to that device. A portion of this device may be adapted to permit it to be folded with the pair of hinged members. The means for folding may, for example, include a living hinge. Additionally, it may be advantageous to provide an edge stiffener along the periphery of one or more of the electrochemical devices. This edge stiffener may provide the benefit of aiding in passive deployment as well as the benefit of providing structural strength.
Another embodiment of the present invention relates to techniques for integrated passive deployment, such as xe2x80x9cliving-hingexe2x80x9d deployment. In this embodiment, the previously described structures may be incorporated into a deployable assembly of electrochemical devices. Preferably, a plurality of these structures may be used to reinforce the assembly, and may, in certain instances, aid in the passive deployment of the assembly.
A further embodiment of the present invention relates to techniques for integrating power cabling and structural support or stiffening. In this embodiment, the previously described structures are combined with integrated power cabling.
It is an object of the present invention to provide a low cost and high specific power solar array for use in, for example, space applications.
It is a further object of the present invention to provide a passive, integrated, foldable, lightweight, deployable spacecraft structure for use with, for example, thin-film photovoltaic arrays.
It is a further object of the present invention to extend the bounds of existing space photovoltaic systems by, for example, combining flexible thin-film photovoltaics with integrated power cabling and stiffening.
It is a further object of the present invention to simplify design techniques by, for example, providing a scalable method for creating deployable space solar arrays.
It is a further object of the present invention to provide an array stiffening method that is adaptable to increasingly efficient photovoltaic design techniques including, for example, developments in multi-junction and polyimide substrate thin-film photovoltaics.
It is a further object of the present invention to provide an array stiffening structure that meets a minimum array natural frequency.
It is a further object of the present invention to provide an array of space photovoltaic cells capable of being supplied with launch restraint protection hardware.
It is a further object of the present invention to provide an array of space photovoltaic cells that may be reliably deployed.
It is a further object of the present invention to provide robust structural protection to an array of space photovoltaic cells.
It is a further object of the present invention to provide a low mass, low cost, and low complexity space solar array by, for example, providing a method for flexible thin-film materials to meet spacecraft requirements.
It is a further object of the present invention to meet spacecraft requirements without bulky, massive, complex, or expensive additional structure.
It is a further object of the present invention to provide an innovative method of stowing, deploying, and stiffening a lightweight, flexible solar array, while minimizing mass.
It is understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The invention is described in terms of arrays of electrochemical devices; however, one skilled in the art will recognize other uses for the invention, such as, arrays of, for example, bioelectric devices. The accompanying drawings illustrating an embodiment of the invention together with the description serve to explain the principles of the invention.